Visible-light-driven photocatalytic degradation of rhodamine B in water by BiOClxI1-x solid solutions

Phospholipid-derived Au and Au-Cu suspensions as efficient peroxide and borohydride activators for organic molecules degradation: Performance and sustainable catalytic mechanism

In the contemporary context, executing light-oxidant- and reductant-driven reactions in solution-phase processes remains challenging mainly due to the lack of general tools for understanding the reactive potential of nano-functional catalysts. In this study, dual-active nanometals (Au and Cu doped with Au) capped within soy lecithin (SL), were developed and characterized, combining flexibility with the catalytic advantages and stability of liquid-phase catalysts. The as-synthesized SL-Au (LG) and SL-Au-Cu (LGC) catalysts were efficiently degraded rhodamine B (RB, 100%) in the presence of H2O2 under light irradiation (350 W lamp) at wide pH range (3-7) within 4.5 h and p-nitrophenol (p-NP, >90% degradation at pH 7) in the presence of NaBH4 under normal stirring with slower kinetics (∼72 h). RB degradation followed a pseudo-second-order kinetic model with a higher r2, and p-NP degradation followed first-order kinetics. The active sites embedded within the structural order of SL arrangement displayed elevated catalytic activity, which was further enhanced by the movement of intermediate/excited states and charged elements within the metal suspended in the phospholipid (LG and LGC). The self-regulating tunability of the physicochemical characteristics of these catalysts provides a convenient and generalizable platform for the transformation of modern dual-active (redox) catalysts into dynamic homogeneous equivalents.

Preparation of floating BiOCl0.6I0.4/ZnO photocatalyst and its inactivation of Microcystis aeruginosa under visible light

Frequent occurrence of harmful algal blooms has already threatened aquatic life and human health. In the present study, floating BiOCl_0.6I_0.4/ZnO photocatalyst was synthesized in situ by water bath method, and and applied in inactivation of Microcystis aeruginosa under visible light. The composition, morphology, chemical states, optical properties of the photocatalyst were also characterized. The results showed that BiOCl_0.6I_0.4 exhibited laminated nanosheet structure with regular shape, and the light response range of the composite BZ/EP-3 (BiOCl_0.6I_0.4/ZnO/EP-3) was tuned from 582 to 638 nm. The results of photocatalytic experiments indicated that BZ/EP-3 composite had stronger photocatalytic activity than a single BiOCl_0.6I_0.4 and ZnO, and the removal rate of chlorophyll a was 89.28% after 6 hr of photocatalytic reaction. The photosynthetic system was destroyed and cell membrane of algae ruptured under photocatalysis, resulting in the decrease of phycobiliprotein components and the release of a large number of ions (K⁺, Ca²⁺ and Mg²⁺). Furthermore, active species trapping experiment determined that holes (h⁺) and superoxide radicals (·O₂^-) were the main active substance for the inactivation of algae, and the p-n mechanism of photocatalyst was proposed. Overall, BZ/EP-3 showed excellent algal removal ability under visible light, providing fundamental theories for practical algae pollution control.

Layered KTO/BiOCl nanostructures for the efficient visible light photocatalytic degradation of harmful dyes

Novel KTO/BiOCl nanostructured photocatalysts with various weight proportions were synthesized using a simple hydrothermal process. The as-prepared nanostructured composite catalysts were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, UV-vis diffused reflectance spectroscopy, Raman spectroscopy, field emission scanning electron microscopy, transmission electron microscopy with high resolution, X-ray photoelectron spectroscopy, and photoluminescence (PL). The photocatalytic activity of prepared catalysts was examined using Rhodamine B (RhB) and Congo Red (CR) as the aimed pollutants. BiOCl nanoparticles were distributed uniformly on the surface of the K₂Ti₄O₉ nanobelts. The optical properties showed that the layered titanate with BiOCl nanostructured photocatalyst displayed improved photoresponsivity due to the narrowed bandgap. The PL results showed that the greater inhibition of the electron-hole recombination process and KTO/BiOCl with a mass proportion of 20% revealed the most favorable photocatalytic behavior. The rate constant of RhB and CR degradation was five times as high as that of the bare BiOCl and titanate. The superior photocatalytic performance was attributed to the advancement of heterojunction between the KTO nanobelt and BiOCl. The KTO/BiOCl nanostructure is a promising visible, active photocatalyst, and the photocatalytic mechanism is discussed using the possible band structures of BiOCl and KTO.

Bismuth Oxyhalide-Based Materials (BiOX: X = Cl, Br, I) and Their Application in Photoelectrocatalytic Degradation of Organic Pollutants in Water: A Review

An important target of photoelectrocatalysis (PEC) technology is the development of semiconductor-based photoelectrodes capable of absorbing solar energy (visible light) and promoting oxidation and reduction reactions. Bismuth oxyhalide-based materials BiOX (X = Cl, Br, and I) meet these requirements. Their crystalline structure, optical and electronic properties, and photocatalytic activity under visible light mean that these materials can be coupled to other semiconductors to develop novel heterostructures for photoelectrochemical degradation systems. This review provides a general overview of controlled BiOX powder synthesis methods, and discusses the optical and structural features of BiOX-based materials, focusing on heterojunction photoanodes. In addition, it summarizes the most recent applications in this field, particularly photoelectrochemical performance, experimental conditions and degradation efficiencies reported for some organic pollutants (e.g., pharmaceuticals, organic dyes, phenolic derivatives, etc.). Finally, as this review seeks to serve as a guide for the characteristics and various properties of these interesting semiconductors, it discusses future PEC-related challenges to explore.